# ^Condition to start relative motion

**^Condition to start relative motion **

Suppose a body A at rest over another body B. Let the limiting friction acing between them is f_{LAB}. If a net force F acts on A which tends to start motion of A relative to B then the condition to start motion of A relative to B is F > f_{LAB}. If F > f_{LAB} then A will remain at rest relative to B. However if

F > f_{LAB }then_{ }A accelerates relative to B & a kinetic friction between A & B acts.